Development partners at eye level

For a gas condensing boiler from Viessmann, ebm-papst developed a complete solution made up of a gas blower, gas valve and gas mixer

March 2013

Nothing is so good that it couldn’t be improved upon,” is Viessmann’s basic principle. With this claim, the company from Allendorf in the German state of Hessen is one of the leading international manufacturers of heating engineering systems. A claim from which the numerous consumers benefit every day, because in times of increasing energy costs, efficient and energy-saving heating solutions benefit not only the wallet, but also the environment. The high investment costs are, however, frequently an inhibitor. With the Vitodens 100, Viessmann therefore has developed a gas condensing boiler which is to provide private households with warmth highly efficiently, and at affordable prices. This appliance solution for the European export market is lightweight and can be mounted on the wall to save space. It is also quiet, uses little energy and uses combustion heat optimally.

Valve for success

The new thing about Vitodens 100 is the modular design. Instead of individual parts, finished modules are installed. “Our objective was to improve maximum efficiency, while also developing a cost-effective solution,” explains Dr. Manfred Dzubiella. “We wanted to increase the degree of modulation and, with it, improve efficiency, while at the same time lowering noise levels and reducing electrical power input. It is not easy to achieve these characteristics all in one.” The Pre-Development Director at Viessmann therefore saw the solution as a complete gas-air mixture and saw the best partner for it in ebm-papst Landshut. At that time, ebm-papst had been providing only the gas blowers.

The system solution tremendously simplifies assembly at Viessmann

“We agreed right away, because that was the opportunity to position ourself as a system supplier,” recalls Christian Diegritz, Head of the Sales Department in the Landshut, Germany plant. The challenge was, however, enormous, because start of production was already scheduled for mid-2011, and a new component also had to be developed: A gas valve that regulates the gas quantity, but also simultaneously safely prevents uncontrolled gas leaks. “That was also the greatest difficulty standing before us,” explains Diegritz. “We have never had a valve like that before.”

Sure, there were already rough preliminary designs, which the Landshut development team took over from the Dungs company, but the finished product was far off in the distance. “That was definitely a challenge for both parties,” Diegritz established, “But there, you see easily how close and great the trust between the R & D departments has become over the years.” A trust that paid off. Because the finished E 01 gas valve stands out significantly from the competition. Through an ingenious design principle, it makes do with 20 percent fewer components. That saves money and space.

Christian Diegritz and Dr. Manfred Dzubiella

Compact solution

A roadblock on the way to the finished system was thus avoided. Now, the E 01 still had to be joined to a gas blower and a gas mixer. With these components, ebm-papst could count on its longtime experience. A venturi mixer provided for the correct gas-air ratio, and the NRG 118 centrifugal blower provided an accurate flow rate. The challenge there was that the three components had to be matched to each other exactly. “Especially when we’re going in the direction of a system, our supplier has to develop an understanding of the entire application and not only work according to specifications,” explains Dzubiella. That meant a lot of co-ordination work between the R&D departments of Viessmann and ebm-papst.

The assembly line of the NRG118 in Landhut

Different settings are necessary depending on the gas type; simultaneously, the emission values have to correspond to the legal requirements. “In this process, it was beneficial that ebm-papst had already consistently invested in experimental laboratories. Without this equipment, such a co-operation would not have been possible,” Dzubiella emphasises. “In this way, we were capable of developing the system with the properties required by us with only a few iteration steps.”

The production of the NRV 118 could finally start. For the product, a separate assembly line was set up in Landshut, with an automatic test rig that was very specifically tailored to the Viessmann system. Installation at Viessmann is then simple, as Dzubiella explains: “We get systems that are set up before-hand, and we just have to install them here; that saves time.” At the bottom line, these customer-specific solutions mean a significant cost savings; because only one supplier is at the beginning of the chain of production, the administrative effort is reduced. Stock-keeping costs are not a factor, because ebm-papst delivers just-in-time. The combination of the three components in one block saves not only material, but also effort for inspection, because the system is already completely tailored to the heating unit. The end customer also needs fewer spare parts for repair purposes.

The test rig of the NRV 118

Active dialogue

This success is also thanks to the longtime partnership of both companies. Once a year, the partners meet for an innovation workshop, at which the developers of both companies present new ideas. Dzubiella describes these processes like this: “We think about where we would like to set new trends and bring them to ebm-papst, who likewise has new ideas. And in this way, a common idea develops, which ends in a new concept.” And there are plenty such ideas. Successor projects have already resulted from the development of the new Vitodens 100, pushing the system understanding even further.